Grading ring



A. HAWLEY 2,007,141

GRADING RING Filed July 12, 1950 Jilly 2, 193,5.

2 Sheets-Sheet l 1 I 0 5 x K 2 24 Patented July 2, 1935 UNITED STATES PATENT OFFICE GRADING RING Application July 12, 1930, Serial No. 467,566

4 Claims.

The invention relates to protective devices for insulators and has particular reference to grading rings provided for stabilizing the electrostatic field about insulators and protecting the insulators themselves against damage in the event of a flash-over or are.

The principal object of the invention, generally stated, is to provide a grading shield or ring which will be, in effect, a single unitary structure and which may therefore be easily handled and. applied in the field to existing installation with a great .degree of simplicity.

An important object of the invention is to provide a grading ring or shield which will be extremely light in weight and yet at the same time strong and rigid, the lightness being of advantage on account of the reduction in the inertia when in applied position and the rigidity being beneficial as preventing distortion of the device during shipment or at any time prior to installation.

Another important object of the invention is to provide a grading shield or ring in which the corona dissipation will be superior to that of the ordinary type of ring and in which the arcing points, in the event of fiashover, will be farther removed from the insulators, as compared with ordinary types of equipment, without increasing the size of the shield or ring.

An additional object is to provide a device of this character which in addition to the advantages above specified will be unusually cheap to manufacture.

To the attainment of the foregoing and other objects and advantages, the invention preferably consists in the details of construction and the arrangement and combination of parts to be hereinafter more fully described and claimed, and illustrated in the accompanying drawings in which:

Figure 1 is a side elevation of a pair of the grading rings mounted at the upper and lower ends of a string of insulators of the clevis type,

Figure 2 is an elevation taken at right angles to Figure 1,

Figure 3 is a fragmentary detail cross sect-ion showing a ring of one cross sectional configuration,

Figure 4 is a similar view showing a modified cross section,

Figure 5 is a cross section showing another modification,

Figures 6 and 7 are elevations of a form of the invention applied to insulators of the ball and socket type.

Referring more particularly to the drawings, it will be observed that in Figures 1 and 2 I have shown a string of insulators ill of the clevis type and that in Figures 6 and 7 I have shown them as of the ball and socket type. It should, however, 5 be understood that this is merely for purposes of illustration as my grading shield may be adapted for use upon insulators of other types well known to the trade, there being no limitation in this respect, Insulators of the type disclosed in Figures 1 and 2 include a porcelain body equipped at the top with a metal cap H terminating in a clevis or spaced ears 12, the porcelain body being also provided at its underside with a pin, not shown in detail but sufficiently represented at [3 in 15 Figure 2, intended to be received and mounted between the ears or within the clevis of the insulator unit next below in the string. Of course the clevis on the uppermost unit is for connection with a supporting structure, tower or the like, not shown, while the pin at the lowermost unit is intended to support a suitable conductor clamp, likewise not shown, as is the common practice.

The advantages of providing some sort of protective shields or rings at the ends of a string of insulators are well known in the art, particularly as disclosed in the patent to Peek granted December 31, 1929, covering improvements in Insulating supports, and numbered 1,741,333 and a discussion of the theories and principles involved is therefore unnecessary. There is conse quently nothing fundamentally novel my idea of applying a pair or rings to the upper and lower ends of a string of insulators, or one ring to one end and arcing horns or the like to the other end. In fact the novel feature of the present invention consists in the actual mechanical construction of the shields or rings.

In accordance with my invention I provide rings indicated as a whole by the numerals l4 and i5 and located at the top and bottom of the string. Though these rings are rather similar in construction they are not identical and it is for this reason that they will be described separately. However, they have many points or features in common, the principal one of which is the formation of the ring in a substantially elliptical shape and from material which is channel shaped or angular in cross section in contradistinction to the usual rod or strap material. Pressed or rolled steel or iron is very suitable for the purpose on account of its lightness and ease of formation into the desired shape. Ordinarily galvanizing will be resorted to for the purpose of preventing corrosion by the weather or by gases and the like in the atmosphere. Ordinarily the upper ring M will be horizontal throughout Whereas it is preferable that the lower ring l5 have diametrically opposite portions slightly upwardly deflected, the purpose being to shorten the arcing distance at the ends of the major axis of the ellipse and thereby remove the flash-over as far as possible from the insulators. Of course the rings might be circular in shape instead of elongated though it is customary to provide elongation in the direction of the conductor which is supported. Another feature common to the upper and also the lower rings is that each is intended to have its ends preferably abutted and welded together so as to avoid the use of multiple parts and securing devices. both rings are shown as provided with a pair of opposed inwardly extending radial arms of angular shape, the arms for the upper ring Hi being indicated at it and those for the lower ring being shown at ll. The arms it are upwardly oiiset with respect to thering Hi and have their lower ends preferably welded thereto, their upper and inner ends being formed withupwardly extendingears 58 which are apertured for the passage of a bolt 19 which not only secures the shield in' place but which also suspends the string of insulators from the support provided for the purpose. -Nut locks 2i) are preferably provided and are peened at one end against the nut or bolt head and at the other end against or about the edges of the ears.

The arms H for the lower ring l5 are offset downwardly with respect thereto and have their upper ends preferably welded to diametrically opposite points on the ring, their lower or inner ends being formed with'upstanding ears 2i disposed against whatever link 22 is provided for suspending the conductor clamp, not shown, the link and the ears being apertured for the passage of securing bolts 23.

As mentioned above, it is preferable, for the sake of lightness and rigidity, that the rings be formed or" material which is angular in cross section. In Figures 1, 2 and 3 the rings are disclosed as formed from a channel bar 2% whereas Figure 4 shows the ring as formed from a bar 25 which is substantially right angular in cross sec-' tion. Not only will rings of thiscross sectional configuration be strong yet light, but at the same time the horizontally extending flange at the upper or lower edge of the ring, as the case' may be, depending upon whether it is the lower or upper ring which is being considered, will serve to remove the corona point farther from the string of insulators and dissipate the corona in a manner which could not be so well accomplished if the ring were made, say, from bar stock circular in cross section, as has been frequently done in the past. This eflect may be further heightened by thinning the edge as shown at 26 in Figure 5.

In the operation, it will be apparent that the rings constructed in accordance with my invention are applied to the upper and lowerunits in a very simple manner by means of bolts provided for the purpose. These rings will act in the same manner as others for the same purpose but it will be noted that each ring, when built, is

complete in itself and is a unitary structure, there being no necessity for assembling any partsrelatively to one another. Theattaching arms are readily secured to the rings as by welding at the plant and the full and complete ring may therefore be shipped out ready for installation in the Furthermore field. As there are no bolts provided for connecting the arms with the rings the material at these points of connection may be kept narrow. Furthermore the construction of the rings from sheet metal pressed into angular or channel shape in cross section provides such stiffness and strength that the rings will be extraordinarily light and this feature permits the use or" attaching arms of minimum size of'stock so that very light material will be necessary in the construction.. 1

In Figures 6 and 7 I have shown the invention modified for application to insulators of the ball and socket type, each insulator W carrying a cap I I with a socket '2'! and provided at its underside with a pin having a ball head 28, the pins and sockets of successive insulators being connected. or course a suitable supporting member 29 is connected with the socket on the uppermost insulator while a link 36 having a socket 3| is connected with the pin of the lowermost. Rings M and 15 are provided and are equipped with arms Ili and li 'The arms te may be continuous with each other and are either centrally apertured or otherwise formed for connection with and are welded to the member 29. The inner ends of the arms ll may be slightly upturned and are welded to the link 30.

This form operates in exactly the same manner as the one first described the only differences being minor details of construction.

From the foregoing description and a study of the drawings it is believed that the construction, operation and advantages will be readily apparent to one skilled in the. art without further explanation.

While I have shown and described the preferred embodiments of the invention, it should be understood that the disclosure is merely an exemplification of the principles involved as the right is reserved to make all such changes in the details of construction as will widen the field of utility and increase the adaptability of the device provided such changes constitute no departure from the spirit of the invention or the scope of the claims hereunto appended.

Having thus described the invention, I claim:

1. Protective apparatusfor a string of suspension insulators, comprising rings of elongated shape located respectively at the top and bottom of the string, the lower ring being dished so that the ends of its major axis in cooperation with the ends of the major axis of the upper ring will provide the shortest gap between the rings for diverting a flash-over are away froro the insulators to the maximum extent, said rings being of channel shape in crosssection with outwardly extending horizontal flanges whereby in the event of a flash-over the arc will occur between the outer edge of the lower flange oi the upper ring and the outer edge of the upper flange of the lower ring.

2. In a protective apparatus for a string of insulators, an arcing ring disposed about one end of the string for cooperation with a ring disposed about the other end, said ring being of channel shape in cross section with outwardly directed upper and lower substantially horizontal flanges the upper flange beingtapered in thickness toward its outer edge and projecting outwardly beyond the lower flange.

3. In a' protective apparatus for a string of insulators, an arcing ring disposed about one end of the string for cooperation with electrode means located at the other end, said ring being of angular shape in cross section and including a substantially vertical flange and a. substantially horizontal flange, said horizontal flange being directed outwardly with respect to the axis of the string whereby the outer edge will itself and without the addition of auxiliary electrode elements constitute an electrode between which and said electrode means an arc may jump in the event of flash-over so that the resultant burning away of the ring will occur only at the edge of the horizontal flange thus leaving the main or vertical portion of the ring unafiected and consequently avoiding burning away of said body portion and interruption in the continuity of the ring.

4. Protective apparatus for a string of suspension insulators comprising rings located respectively at the top and bottom of the string, said rings being of channel shape in cross section with outwardly extending horizontal flanges whereby in the event of a flash-over the arc will occur between the outer edge of the lower flange of the upper ring and the outer edge of the up- 10 per flange of the lower ring.

KENT A. HAWLEY. 

